Method of constructing tire and identification tag therefor

ABSTRACT

Method of constructing pneumatic tire where at least one ot its elements is comprised of a heat-curable rubber composition, an improvement in which such composition is identified with a releasably attached identification tag containing an information-providing ink composition thereon, wherein the ink composition contains a heat activatable blowing agent. The invention further relates to the heat-curable rubber composition so-identified and also to the identification tag itself.

TECHNICAL FIELD

This invention relates to a method of building heat-cured rubberarticles such as a pneumatic tire and to the corresponding article ortire. The invention further relates to identification tags forcomponents for such articles and such tagged components. The inventionadditionally relates to the preparation or construction of a curedrubber tire from individually compounded, optionally shaped, rubbercomponents.

BACKGROUND

Pneumatic rubber tires can conveniently be prepared by buildingpreviously compounded and shaped rubber components such as tread stockand sidewall stock onto a rubberized fabric carcass. The carcassincluding an inner liner of rubber gum stock. The prepared tire is thenshaped and cured by application of heat and pressure.

An inherent difficulty involved in such tire preparation involves thestorage and identification of individual compounded components prior totheir utilization.

It is important to appreciate that, once the rubber is compounded withvarious materials including a curative therefor, it becomes a tacky,chemically active, productive stock. It is designed to be cured uponapplication of heat, or elevated temperature. It must be used in arelatively short time or it becomes aged or degraded.

It is further important to appreciate that such compounded rubbercomponents must be identified in some manner, usually by rubbercompound, batch number and preparation date, so that they are not storedfor too long a period before use and so they are built into the correcttire construction.

Such identification is often accomplished by loosely or releasablyattaching or applying an identification tag to the compounded rubbercomponent.

If such an identification tag should, by accident not be removed fromits labeled rubber component, the tag could conceivably become embeddedwithin the elements of the tire construction and become a foreignmaterial to the tire which, after fabrication, shaping and curing of thetire, might not be readily visually detected.

DISCLOSURE AND PRACTICE OF THE INVENTION

In accordance with this invention, in a method of constructing apneumatic or semi-pneumatic tire by the process of building its elementstogether followed by shaping and curing the construction where at leastone of its elements is comprised of a heat-curable rubber composition,the improvement in which at least one of said rubber compositionelements is identified prior to building it into the tire constructionby a paper identification tag having a surface area of one of its twosides in the range of about 2 to about 30, preferably about 5 to about16 square inches (in²) releasably attached thereto having a printed inkcomposition thereon which covers about 10 to about 50, preferably about20 to about 40 percent of the surface area of at least one side of saidtag where said ink composition contains about 5 to about 25, preferablyabout 8 to about 15 weight percent, based on the total ink composition,of a heat activatible blowing agent.

The invention further relates to said identification tag.

The invention additionally relates to such tagged heat-curable rubbercomposition.

In the practice of building a tire, the identification tag is to beremoved from its corresponding element prior to building the elementinto the tire construction.

In the practice of this invention, the tag is releasably attached tosaid heat-curable composition in a manner so that it can relativelyeasily be removed. For example, it might be attached with a small wirestring or twine to the composition.

However, if, by mistake such tag should remain with its correspondingelement or, in some other manner is built into the tire, following whichit is cured therein, the value of the invention is particularlyappreciated.

In said instance, the invention is demonstrated where, in thepreparation of a pneumatic or semi-pneumatic tire where such tag isbuilt into and within the tire construction following which theconstruction is shaped and cured at a temperature in the range of about90° C. to about 150° C. the blowing agent in the ink composition on thetag is heat activated to release a gas to form a raised bubble orblister on the surface (inner or outer) of the hot tire after the tire'sremoval from its mold. This is particularly evident if the tag istrapped between an inner or outer layer of the tire and its supportingcarcass ply. Such raised area or bubble or blister on the hot tire isnormally about the size and shape of the tag, or at least about the sizeand shape of its inked portion and is generally easily and relativelyquickly detected by visual inspection.

In the description of this invention, the identification tag isdescribed as being of paper. In this regard, it is considered that paperis to be used in its broad sense as relating to paper stock having ageneral thickness in the range from about 0.002 to about 0.02,preferably about 0.003 to about 0.015, inches which also includes whatis sometimes referred to as card or cardboard stock.

The ink for such tag is considered to be of conventional compositioncomprised of, for example, various conventional elements such as carbonblack, various resin oils, toners and solvents. Indeed, the ink is oftenconsidered simply as somewhat of a carrier for the blowing agent.

In practice of this invention, it is normally desired that the inkcomposition, inclusive of solvent, contains about 5 to about 25 weightpercent of the heat-activatible blowing agent.

The ink composition containing the blowing agent is simply printed ontothe tag and allowed to dry in a conventional manner. The solvent isconsidered a minor portion of the ink composition (5-10 percent).

It is considered that preparation of the ink, its recipe, and theprinting of the tag is done by rather conventional processes and methodswell known to those having skill in these arts.

It is generally desired that the blowing agent be heat activatible at orless then the curing temperature of the tire but sufficiently aboveambient room or factory temperature (20° C. to 45° C.) to prevent orinhibit premature blowing. A desired heat activation temperature rangeis for the blowing agent about 90° C. to about 150° C.

Upon heat activation, of course, the blowing agent breaks down orchemically decomposes to release the gaseous element or compound suchas, for example, nitrogen or carbon dioxide, preferably nitrogen.

Representative of various heat activatible blowing agents are, forexample, diazoaminobenzene, N,N'-dimethyl-N,N'-dinitrosoterephthalamide,benzensulfonyl hydrazide and sodium bicarbonate/stearic acid.

The practice of this invention is further illustrated by reference tothe following example which is intended to be representative rather thanrestrictive of the scope of the invention. Unless otherwise indicated,all parts and percentages are by weight.

EXAMPLE I

For the purpose of illustrating this invention, several radial ply,tubeless pneumatic rubber ties of size P 205/75R15 were built on abuilding drum which were constructed of elements which included theconventional inner liner rubber gum stock, fabric-reinforced rubberizedcarcass and belt, beads and apex, pre-extruded sidewall rubbercompositions and pre-extruded tread rubber compositions.

A heavy paper (cardboard) tag containing printed identification thereonfor said sidewall element with its ink containing a heat activatibleblowing agent was purposely built into the tire constructions in variousplaces. For example, in one tire it was placed between the inner surfaceof the outer sidewall element and the outer surface of its supportingcarcass ply element and in another tire it was placed between the innerliner and the fabric-reinforced carcass.

The constructed tires were placed in a tire mold and cured at atemperature in the range of about 100° C. to about 150° C.

Upon removal from the mold, in one tire it was observed that the innerliner was ruptured at the position of the tag, apparently due to the gasreleased by the blowing agent. In another hot tire a blister about thesize of the tag and about 3/4 inch thick was easily visable on itssidewall.

The tag was about 0.009 inch thick, 2.3 inches wide and 4.8 inches long.The ink of the printed matter covered about 35 percent of the area ofone side of the tag. Thus the ink had a surface area of about 4 in². Theink had an estimated weight of about 4.3×10⁻² grams. The ink containedabout 15 weight percent heat activatible blowing agent on a dry weightbasis. Therefore, the tag represented about 6.4×10⁻³ grams blowing agentfor a tag surface area of about 11 in². The ink itself was consideredsomewhat conventional in nature.

What is claimed is:
 1. An identification paper tag having a surface areaof one of its two sides in the range of about 2 to about 30, preferablyabout 5 to about 16 square inches (in²) and having aninformation-providing ink composition thereon which covers about 10 toabout 50, preferably about 20 to about 40 percent of the surface area ofat least one side of said tag where said ink composition contains about5 to about 25, preferably about 8 to about 15 weight percent, based onthe total ink composition, of a heat activatable blowing agent.
 2. Theidentification tag of claim 1 where said paper tag has a thickness inthe range of about 0.002 to about 0.02 inches where the area of one ofits two sides is in the range of about 5 to about 16 square inches, theink composition covers about 20 to about 40 percent of the surface of atleast one side of the tag, the ink composition contains about 8 to about15 weight percent heat activatable blowing agent, where said blowing isheat activatable in a temperature range of about 90° C. to about 150° C.to release nitrogen gas.
 3. The identification tag of claim 1 where saidblowing agent is selected from at least one of diazoaminobenzene,N,N'-dimethyl-N,N'-dinitrosoterephthalamide, benzensulfonyl hydrazideand sodium bicarbonate/stearic acid.